The Maillard reaction ( sugar-amine condensation reaction [1] ) is a chemical reaction between amino acids and sugars that occurs when heated. An example of such a reaction is roasting meat or baking bread, during which a typical smell, color and taste of cooked food occurs during the heating of a food product. These changes are caused by the formation of Maillard reaction products. Named after the French chemist and doctor Louis Camille Mayard , who was one of the first to study the reaction in the 1910s.
Content
Chemistry
The reaction involves several steps:
- The reactive carbonyl group of sugar (in its open conformation) interacts with the nucleophilic group of the amino acid to form an unstable N-substituted glycosylamine and water.
- Glycosylamine spontaneously undergoes Amadori rearrangement and turns into ketosamine .
- Ketosamines in the course of subsequent reactions can turn into:
- gearboxes
- short chain hydrolytic products ( diacetyl , aspirin , pyruvaldehyde , etc.) or
- brown nitrogenic polymers and melanoidins .
Different sugars have different reactivity. Sugar reactivity follows this order: pentose > hexose > disaccharide . For example, fructose is 100-200 times more active than glucose . The Maillard reaction leads to the formation of numerous products, sometimes with a rather complex and often still unknown structure.
Industry
The food industry produces many Maillard reaction products, which are used to give the desired taste and smell to food products. In food chemistry, it is known as the sugar-amine reaction [1] .
Medicine
Maillard reaction occurs not only during cooking. This reaction between amino acids and sugars (the so-called glycation ) occurs in a living organism [2] . Under normal conditions, the reaction rate is so slow that its products manage to be removed. However, with a sharp increase in blood sugar in diabetes, the reaction is significantly accelerated, the products accumulate and can cause numerous disorders (for example, hyperlipidemia ). This is especially pronounced in the blood, where the level of damaged proteins rises sharply (for example, the concentration of glycosylated hemoglobin is an indicator of the degree of diabetes compensation). The accumulation of altered proteins in the lens causes severe visual impairment in patients with diabetes. However, there is evidence of http://humbio.ru/humbio/starenie/0000c7e9.htm#0000dd86.htm that "The negative effect of glycosylation is determined not by glucose attachment to long-lived proteins, but by oxidative damage caused by free radicals." Such radicals include ketones entering the bloodstream with a lack of glucose in the cell and a violation of the CTK. http://medic.studio/patologicheskaya-fiziologiya/narushenie-regulyatsii-uglevodnogo-71203.html "Most of the free fatty acids in the absence of insulin are oxidized in the liver only to acetyl-CoA, from which then, under conditions of delayed resynthesis of fatty acids from ketone bodies — acetoacetic and P-hydroxybutyric acids and acetone — are formed due to NADP + deficiency and suppression of the Krebs cycle, with hyperketonemia up to 5–7 mmol / L, ketonuria 140 mg / day (normal 10–30 mg / day). to inhibition of muscle use of glucose, and therefore contributes to the accumulation of glucose in blood. "
The accumulation of some late Maillard reaction products, as well as oxidation products that occur with age, leads to age-related changes in tissues [3] . No drugs have been found that can inhibit the Maillard reaction in the body, although some agents ( aminoguanidine ) significantly reduce the in vitro reaction. The most common late reaction product is carboxymethyl lysine , a derivative of lysine . Protein carboxymethyllysine serves as a biomarker of the general oxidative stress of the body. It accumulates with age in tissues, for example, in skin collagen , and is elevated in diabetes.
Reaction Products
Examples of reaction products:
- 6-acetyl-1,2,3,4-tetrahydropyridine - the smell of baked bread, biscuit.
- 2-acetyl-1-pyrroline - the smell of cooked rice.
History
Despite the fact that the reaction is named after Louis Camille Mayard, the reaction mechanism was investigated and described only in 1953 by the American chemist John Edward Hodge in the article “Chemistry of reactions with darkening in model systems” [4] . In the article, Hodge proposed a Maillard reaction scheme, which became known as the "Hodge scheme". Hodge's contribution to the study of the Maillard reaction was little known for a long time [5] [6] , however, in 1979, Hodge's article was recognized as classical due to the large number of references to it in other scientific works.
See also
- Glycation
- Melanoidins
Notes
- ↑ 1 2 The omnipresent reaction of Maillard // Chemistry and Life No. 2, 2012
- ↑ Grandhee, SK; Monnier, VM Mechanism of formation of the Maillard protein cross-link pentosidine. Glucose, fructose, and ascorbate as pentosidine precursors (English) // J. Biol. Chem. : journal. - 1991 .-- 25 June ( vol. 266 , no. 18 ). - P. 11649-11653 . - PMID 1904866 .
- ↑ Advanced Glycation End Products (AGEs): A Complete Overview . healthline.com .
- ↑ JE Hodge. Dehydrated Foods, Chemistry of Browning Reactions in Model Systems // Journal of Agricultural and Food Chemistry. - 1953-10-01. - T. 1 , no. 15 . - S. 928-943 . - ISSN 0021-8561 . - DOI : 10.1021 / jf60015a004 .
- ↑ The Black male in white America . - Hauppauge, NY: Nova Science Publishers, 2002 .-- P. ix, 227. - ISBN 9781590333709 .
- ↑ Sergey Belkov. Reaction flavors . Date of appeal September 23, 2017.